Dyes for anisotropic dye films, dye compositions for anisotropic dye films, anisotropic dye films and polarizing elements

Abstract

An anisotropic dye film having high dichromatic properties is provided. An anisotropic dye film wherein the period d attributable to molecular stacking is at most 3.445 Å, and the column length L thereof is at least 105 Å. The anisotropic dye film preferably has a degree of orientation of the molecular stacking axes of at least 85% and a film thickness of at most 30 μm, and is formed by a wet film-forming method. Since it has a molecular alignment suitable to develop a dichroic ratio, it provides high dichromatic properties. A polarizing element having this anisotropic dye film is excellent in heat resistance, light fastness and polarizing performance.

1. An anisotropic dye film comprising a molecularly stacked dye wherein a period attributable to molecular stacking is at most 3.445 Å, and a column length thereof is at least 105 Å. 
     
     
       2. The anisotropic dye film according to  claim 1 , wherein the degree of orientation of the molecular stacking axes is at least 85%. 
     
     
       3. The anisotropic dye film according to  claim 1 , wherein a film thickness is at most 30 μm. 
     
     
       4. The anisotropic dye film according to  claim 1 , wherein the anisotropic dye film is formed on a substrate. 
     
     
       5. The anisotropic dye film according to  claim 4 , wherein the anisotropic dye film is formed by a wet film-forming method. 
     
     
       6. The anisotropic dye film according to  claim 4 , wherein the substrate is glass or a resin film. 
     
     
       7. The anisotropic dye film according to  claim 1 , wherein a protective layer is further formed. 
     
     
       8. The anisotropic dye film according to  claim 1 , comprising an azo dye, wherein the azo dye is represented in the free acid form by the following formula (1): 
       
         
           
           
               
               
           
         
       
       wherein
 A 0  represents a phenyl group or a naphthyl group, either of which may have one or more substituents selected from the group consisting of a sulfo group, a carboxyl group, a hydroxyl group and an amino group, 
 B 0 , C 0  and D 0  independently of one another represent aromatic hydrocarbon rings having a carbon number of from about 6 to about 20, which may have one or more substituents selected from the group consisting of an alkyl group, an alkoxy group, and an acylamino group, 
 R 0  represents a hydrogen atom or an optional substituent, 
 each of X 0  and Y 0  independently of each other, represents an optional substituent other than a halogen atom, 
 k represents 1 or 2, and m represents 1 or 2, provided that when k is 2, the plurality of B 0  contained in one molecule may be the same or different. 
 
     
     
       9. The anisotropic dye film according to  claim 8 , wherein the azo dye, in the free acid form is represented by the following formula (1-a): 
       
         
           
           
               
               
           
         
       
       wherein
 A 1  represents a phenyl group or a naphthyl group which may have one or more substituents selected from the group consisting of a sulfo group, a carboxyl group, a hydroxyl group and an amino group, 
 each of B 1  and C 1  independently of each other, represents a phenylene group or a naphthylene group either of which may have one or more substituents selected from the group consisting of an alkyl group, an alkoxy group and an acylamino group, 
 R 5  represents a hydrogen atom or a C 1-5  alkyl group which may have a substituent, 
 each of X 1  and Y 1  independently of each other, represents a —NR 1 R 2  group, a —OR 3  group or a —SR 4  group, 
 provided that each of R 1 , R 2 , R 3  and R 4  independently of one another, represents a hydrogen atom, a C 1-8  alkyl group which may have a substituent, a C 2-18  alkenyl group which may have a substituent, a C 3-5  hydrocarbon ring group which may have a substituent, or a heterocyclic group consisting of a 5- or 6-membered monocyclic ring or a condensed ring of two or three such monocyclic rings, which may have a substituent, or R 1  and R 2  may be mutually bonded to form a 5- or 6-membered ring containing a nitrogen atom, and the ring formed by bonding of R 1  and R 2 , may have a substituent, 
 k represents 1 or 2, and m represents 1 or 2, provided that when k is 2, the plurality of B 1  contained in one molecule, may be the same or different. 
 
     
     
       10. The anisotropic dye film according to  claim 1 , comprising an azo dye, wherein the azo dye is represented in the free acid form by the following formula (2): 
       
         
           
           
               
               
           
         
         wherein each of D 1  and E 1  independently of each other, represents a phenylene group which-is optionally substituted, or a naphthylene group which is optionally substituted, wherein 
         the phenylene group is optionally substituted with a group of low polarity, and 
         the naphthylene group is optionally substituted with a group of low polarity, 
         G 1  represents a carboxyl group, a sulfo group or a phosphonic group, 
         Q 1  represents a halogen atom, a hydroxyl group, a nitro group, an amino group which is optionally substituted, a C 1-4  alkyl group which is optionally substituted, a C 1-3  alkoxy group which is optionally substituted, a carboxyl group or a sulfo group, 
         each of Q 2  and Q 3  independently of each other, represents a hydrogen atom, a C 1-4  alkyl group which is optionally substituted, or a phenyl group which is optionally substituted, 
         p represents 0 or 1, and t represents 1 or 2. 
       
     
     
       11. An azo dye, of which the free acid form is represented by the following formula (1): 
       
         
           
           
               
               
           
         
       
       wherein
 A 0  represents a phenyl group or a naphthyl group, either of which may have one or more substituents selected from the group consisting of a sulfo group, a carboxyl group, a hydroxyl group and an amino group, 
 B 0 , C 0  and D 0  independently of one another represent aromatic hydrocarbon rings having a carbon number of from about 6 to about 20, which may have one or more substituents selected from the group consisting of an alkyl group, an alkoxy group and an acylamino group, 
 R 0  represents a hydrogen atom or an optional substituent, 
 each of X 0  and Y 0  which are independent of each other, represents an optional substituent other than a halogen atom, 
 k represents 1 or 2, and m represents 1 or 2, provided that when k is 2, the plurality of B 0  contained in one molecule may be the same or different. 
 
     
     
       12. The azo dye according to  claim 11 , wherein the free acid form is represented by the following formula (1-a): 
       
         
           
           
               
               
           
         
       
       wherein
 A 1  represents a phenyl group or a naphthyl group which may have one or more substituents selected from the group consisting of a sulfo group, a carboxyl group, a hydroxyl group and an amino group, 
 each of B 1  and C 1  independently of each other, represents a phenylene group which may have a substituent, or a naphthylene group, either of which may have one or more substituents selected from the group consisting of an alkyl group, an alkoxy group and an acylamino group, 
 R 5  represents a hydrogen atom or a C 1-5  alkyl group which may have a substituent, 
 each of X 1  and Y 1  independently of each other, represents a —NR 1 R 2  group, a —OR 3  group or a —SR 4  group, 
 provided that each of R 1 , R 2 , R 3  and R 4  independently of one another, represents a hydrogen atom, a C 1-18  alkyl group which may have a substituent, a C 2-18  alkenyl group which may have a substituent, a C 3-15  hydrocarbon ring group which may have a substituent, or a heterocyclic group consisting of a 5- or 6-membered monocyclic ring or a condensed ring of two or three such monocyclic rings, which may have a substituent, or R 1  and R 2  may be mutually bonded to form a 5- or 6-membered ring containing a nitrogen atom, and the ring formed by bonding of R 1  and R 2 , may have a substituent, 
 k represents 1 or 2, and m represents 1 or 2, provided that when k is 2, the plurality of B 1  contained in one molecule, may be the same or different. 
 
     
     
       13. The azo dye according to  claim 11 , which has a molecular weight of from 500 to 5,000. 
     
     
       14. An azo dye for an anisotropic dye film to be formed by a wet film-forming method, wherein the azo dye in the free acid form is represented by the following formula (2): 
       
         
           
           
               
               
           
         
         wherein each of D 1  and E 1  independently of each other, represents a phenylene group which is optionally substituted, or a naphthylene group which is optionally substituted, 
       
       wherein
 the phenylene group is optionally substituted with a group of low polarity, and 
 the naphthylene group is optionally substituted with a group of low polarity, 
 G 1  represents a carboxyl group, a sulfo group or a phosphonic group, 
 Q 1  represents a halogen atom, a hydroxyl group, a nitro group, an amino group which is optionally substituted, a C 1-4  alkyl group which is optionally substituted, a C 1-3  alkoxy group which is optionally substituted, a carboxyl group or a sulfo group, 
 each of Q 2  and Q 3  which are independent of each other, represents a hydrogen atom, a C 1-4  alkyl group which is optionally substituted, or a phenyl group which is optionally substituted, 
 p represents 0 or 1, and t represents 1 or 2. 
 
     
     
       15. The azo dye according to  claim 14 , wherein the dye has an excitation purity of from 0 to 12%. 
     
     
       16. A dye composition for an anisotropic dye film, comprising the azo dye as defined in  claim 11 . 
     
     
       17. An anisotropic dye film, comprising the azo dye as defined in  claim 11 . 
     
     
       18. An anisotropic dye film formed by using the dye composition for an anisotropic dye film as defined in  claim 16 . 
     
     
       19. A polarizing element comprising the anisotropic dye film as defined in  claim 1 . 
     
     
       20. A dye composition for an anisotropic dye film, comprising the azo dye as defined in  claim 14 . 
     
     
       21. An anisotropic dye film, comprising the azo dye as defined in  claim 14 . 
     
     
       22. An anisotropic dye film formed by using the dye composition for an anisotropic dye film as defined in  claim 20 . 
     
     
       23. A polarizing element comprising the anisotropic dye film as defined in  claim 17 . 
     
     
       24. A polarizing element comprising the anisotropic dye film as defined in  claim 18 . 
     
     
       25. A polarizing element comprising the anisotropic dye film as defined in  claim 21 . 
     
     
       26. A polarizing element comprising the anisotropic dye film as defined in  claim 22 .